Emitec produces a partial flow filter (as opposed to a wall flow filter) made of metal and uses a passively regenerated cleaning system. This means that the soot collected from the exhaust is catalytically combusted with NO2 generated upstream in the engine. Downey explained that the benefit to this system is a more stable operating system, which makes it easier to be retrofitted. The DPFs can be used on large diesel engines (i.e., buses or trucks) or on diesel engines in smaller passenger cars. Some companies, like MAN, use Emitec filters as a first-fit. Downey said that most of the company's testing is done in Europe using ULSD, but he figures that a standardized biodiesel - should such a thing ever be widely available - would not pose a problem for the Emitec filters.
Emitec's press release is pasted after the jump. (UPDATE: updated release)
Emitec SCRi™ System Moves Automakers Closer To Meeting U.S. Emissions Standards
DETROIT, April 14, 2008 – Emitec has developed an integrated particulate matter (PM) and selective catalytic reduction (SCR) system, SCRi™, for light- and heavy-duty diesel applications. The SCRi™ combines Emitec's partial flow filter, PM-METALIT®, which is proven in mass production with various OEM's since 2004, and a new highly effective turbulent SCR catalyst into one cost-effective and maintenance-free system.
It is the first continuously operating system that reduces both particulate matter and nitrogen oxides (NOx) simultaneously, and can aid automakers in their efforts to meet stricter emission and fuel efficiency standards.
The SCRi™ system works in three steps. First, the exhaust gas passes through an oxidation catalyst to eliminate harmful hydrocarbon and carbon monoxide emissions and at the same time oxidize nitrogen oxide to nitrogen dioxide. By using Emitec's patented turbulent LS foils, the volume of this oxidation catalyst could be reduced by approximately one-quarter.
Secondly, urea (AdBlue) is injected into the exhaust stream and routed into a second module, consisting of a PM-METALIT® followed by a turbulent SCR catalyst. In the coated PM-METALIT®, the injected AdBlue is converted to ammonia, a reducing agent, while at the same time fine particles are continuously filtered and oxidized. In contrast to other particle filtration devices, Emitec's PM-METALIT® does not need periodic active regeneration and ash removal maintenance.
Finally, the filtered exhaust gas and the reducing agent simultaneously pass over a highly efficient and compact SCR catalyst, where nitrogen oxide is reduced to harmless nitrogen and water. This SCR catalyst uses a combination of Emitec's turbulent longitudinal (LS) and perforated (PE) foils, making it possible to reduce the catalyst volume by approximately one-third and fit it together with the PM-METALIT® inside a compact housing.
Diesel passenger cars from several original equipment manufacturers are being fitted with the SCRi™ system in both the United States and Europe.
Emitec GmbH is the leading designer and manufacturer of metallic substrates METALIT® and diesel PM-METALIT® for exhaust gas aftertreatment and evaporative emissions. Its METALIT® products are used by nearly every major automaker worldwide. Founded in 1986, Emitec is headquartered in Lohmar, Germany and currently holds more than 1,700 international patents. The company's North American operations, Emitec Inc., are headquartered in Auburn Hills, Mich. Manufacturing facilities are located in Fountain Inn, S.C. as well as Lohmar and Eisenach, Germany, and Pune, India. For more information on Emitec, visit www.emitec.com.
[Source: Emitec Inc.]